Ectopic eruption of a mandibular first permanent molar: report of an unusual case.

A case history of an ectopically erupting mandibular left first permanent molar is described. Most notable are the unusual findings of a missing mandibular left second premolar and an epithelial cyst and a horizontally impacted mandibular left second permanent molar. A unique treatment plan called for the extraction of the mandibular second primary molar, excision of the cyst, and removal of the mandibular left second and third molars. In hindsight, other procedures might have served the patient better.